Study of the Response Time and Sensitivity of the MG-32 Pyroelectric Detector with a Polypropylene Window in the Visible Range

The response time and sensitivity in the visible spectral range of a commercial MG-32 pyroelectric detector based on the organic crystal of tetraaminodiphenyl (NZPP Vostok JSC) with a 0. 5 mm thick polypropylene input window are studied. The sensor time constant is varied by connecting a capacitance C in the range from 2 nF to 3. 8 F to the feedback circuit of the receiver amplifier. With increasing capacitance in the range of 0. 1–3. 8 F, the receiver time constant increased linearly from 0. 2 to 5 ms, and at lower capacitances it reached saturation, setting a limit of 25 s. The voltage sensitivity is tested using a diode laser (=637 nm) ; at C=0. 1 F, it is 3600 V W ^-1, which is 8 \% less than the sensitivity of the receiver without a polypropylene window. The equivalent noise power is virtually independent of the feedback capacitance in the range of C=0. 002-0. 1 F and is 0. 8 10^-10 W Hz ^-1/2, while the detectivity is 10^9 cm W Hz ^-1/2. These characteristics are approximately one or two orders of magnitude superior to those of other commercial pyroelectric detectors and the Golay optoacoustic cell, making the receiver under study quite promising and versatile for many applications.